Telephone-exchange system



H. P. CLAUSEN.

TELEPHONE EXCHANGE SYSTEM.

APPLICATlON FILED SEPT. 25.'1916.

1,378,938. Patented May 24,1921,

N lnve mar: N Henry F C/ausen.

" ii I W W l O J I H Afiy UNITED STATES PATENT OFFICE.

HENRY r. GLAUSEN, or lvroun'rvnnnon, NEW YORK; AssIe-NoR-ro wEsrERN ELEG- TRIO COMPANY, InooRroR 'rEn,orNnW'YonK, N. Y., A CORPORATION or NEW YORK;

T 0 all whom it may concern Be it known that I, HENRY P. CLAUSEN, a

citizen of the United States, residing at Mount Vernon, in the county of Vestchester and State of New York, have invented certain new and useful Improvements in'Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact dey scription.

This invention relates to telephone ex} change systems, its object being the production of improved signaling means for such systems.

In accordance with. a feature of this invention, should the incoming end of a'trunk circuit be connected with a busy line, a signaling device will be operated to furnish a signal indicating that fact. t More specifically stated, a calling supcr visory lamp associated with a cord circuit connected with the trunlrcircuit and a supervisory lamp associated with the trunk circuit are lighted intermittently orjperiodically whenever the trunk circuit is connected with a busy telephone line,whereby a distinctive signal is furnished both operators. For a more complete understanding oi thisinvention, reference should be had to the following description'taken in connection with the drawing in which is shown a calling telephone line A terminating at one central oihce, a called telephone line B terminating at another central.olfice,-the calling line being connected to a cord circuit C,

which in turn may be connected to a trunk circuit D for establishing connections with the called line B. It is to be understood that a number of telephone lines similar-to A tions, as is the usual practice. For the sake.

of simplicity, however, only two telephone lines, one cord circuit and one trunk circuit,

are illustrated; in the drawing. It .is believed that this invention will be fullyunrf derstood from a description of the operatipn of the system shown'ln the drawlng,

audit will be so described.v v

Assumingthat the operator at whose po sition cord circuit Cis located has beenad- TELEPHONE-EXCHANGE SYSTEM.

i Specification of 'Letters Patent. Patented lu 24 1921 Applicationfiled'september 25, 1916. Serial No. 122,011. i i

vised that the subscriber on the connected calling line Adesires to be connected with subscribei B wlioseline terminates in another central ofiice, the operator at the originating central oflice will communicate the number of the desired line to the operator at the terminating central office over a call w re circuit (not shown) and W111 receivea trunk assignment. Assuming trunk circuit D has been assigned, the opthat the erator at the originating office inserts the the left-hand winding of relay 6 is of high resistance,supervisory relay 22 in the cord circuit does not now operate. Upon the 0peration of relay 6, lamp 7 at the incoming end of the trunk circuit will be lighted over a circuit'from battery through the normal contact. of relay 8, lamp 7, contact of relay 6 and lower normal contact of relay .9 and resistance 10' to ground. The lighting of this lamp will indicate'tothe terminating operator that, connection has been made with the proper trunk circuit. i

The terminating operator will thereupon, after testing Bs line and finding it idle, insertv the plug of the trunk circuit D into a jack associated with Bs line, whereupon l relay .9 willbe operated over a circuit from battery throughthe normal contact of relay 8, lamp 7, winding of relay9, sleeve contacts of the plug and jack the windingfof cutoft relay 15 to ground. The operation otrelay 9 causes the operation of slow-opcrating ringing relay 16 Over a circuit from battery through the winding of relay 16, normal contact of relay 17, contact of tr1pping relay 18, lower alternate contact of relay 9, contact of relay 6, winding of relay 9, sleeve contacts of the plug and jack and the winding of cut-off relay to ground; The

winding ofringing relay 16 is now bridged in parallel with the lamp 7 and eflacesthis lamp. f The operation of ringing relay 16 connects a source of ringing current 19 through the wind-mg oftrippmg relay 18 to i the. called line for operating the call bell at the station connected with the line. r-The opq eration of the ringing relay l6 also causes the operation'of relay 14 over a circuit from battery: through the winding of relay 14,

lower alternate contact of ringing relay 16 and upper alternate contact of relay 9 to ground. Relay 14, in operating, establishes a locking circuit for itself through its alter nate contact.

In response to the operation of the call bell, subscriber B removes his receiver from the switchhook, causing the operation of tripping relay 18, whereupon winding 20 of relay 17 is included in circuit with the ringing relay 16. Relay 17 thereupon operates and establishes a locking circuit for itself from battery through the left-hand alterate contact and winding 20 of relay 17 lower alternate contact of relay 9, contact of relay 6, sleeve contacts of the plug and jack and the winding of cut-off relay 15 to ground. \Vinding 20 of relay 17 is now substituted for the winding of ringing relay 16 and the lamp 7 remains effaced. The closure of the left-hand alternate contact of relay 17 establishes a short circuit for the ringing relay 16 which thereupon releases, disconnecting the source of ringing current from the called line. The release of ringing relay 16 permits the operation of supervisory relay 21, which, in operating, completes the circuit for the right-hand winding of relay 6 which is thereupon placed in parallel with the left-hand winding and reduces the resistance of the circuit including the supervisory relay 22, permitting an increased flow of current through thesupervisory relay 22 which thereupon operates to etface the calling supervisory lamp 5, indicating to the operator at the originating central office that the called party has answered.

Upon completion of the conversation, the subscribers restore the receivers to the switchhooks, whereupon supervisory relay 21 isreleased, opening the circuit through the right-hand winding of relay 6. Supervisory relay 22 in the cord circuit C is thereby released, causing the supervisory lamp5 to light to furnish a disconnect signal.

Upon the removal of the calling plug of the cord circuit C from the jack of the trunk circuit D, relay 6 releases opening the shunt circuit about the lamp 7 whereupon the lamp lights to furnish a disconnect signal to the terminating operator. The terminating operator, observing the lighted condition of lamp 7, thereupon removes the plug from the jack of Bs line, whereupon all i apparatus associated with the trunk circuit will be returned to normal position.

Assuming that the terminating operator disregards the usual busy test signal or does not make the test and inserts the plug of the trunk circuit into a jack of Bs line at the time this line isbusy. The relay 9 cperates, as before described, and upon its operation, supervisory relay 21 operates over the line circuit, the receiver of the station on that line being off the switchhook. Re-

,cating that fact.

lay 21, in operating, connects the right-hand winding of relay 6 in parallel withthe lefthand winding, thereby decreasing the resistance in circuit with relay 22 which operates to efface the supervisory lamp 5, which remains effaced for only a short time, as will hereinafter more fully appear. The operation of relay 21 also causes the operation of relay 17 over a circuit from battery through upper alternate contact of relay 21, winding 25 and normal contact of relay 17, normal contact of tripping relay 18, lower alternate contact of relay 9, contact of relay 6, winding of relay 9, sleeve contacts of the plug and jack and the winding of cutoff relay 15 to ground. Relay 17, in operating, establishes a locking circuit for itself through its left-hand alternate contact and winding 20 thereof, and in addition, causes the operation of relay 8 over a circuit from batter through the winding of relay 8, rightand alternate contact of relay 17, normal contact of relay 14 and upper alternate contact of relay 9 to ground, Relay 8, in operating, establishes a locking circuit for itself through its left-hand alternate contact, normal contact of relay 11 and upper alternate contact of relay 9. The operation of relay 17 short circuits the winding of, and prevents the operation of ringing relay 16, whereby ringing current is prevented from being connected to a busy line to which the trunk circuit has been connected. The operation of relay 8 also removes a short circuit from the winding of V a high-resistance relay 26 effa-cingthe lamp 7. The relay 26 also operates openingits contact which is-in series with the righthand windingof relay 6 and the lower con tact of supervisory relay 21, so that the resistance in circuit with relay 22 is increased causing the release of relay 22 to light the the resistance in circuit with the supervisory relay 22, which thereupon operates to efi'ace the supervisory lamp 5. The calling supervisory lamp 5 is thereby intermittently lighted whenever the plug of the trunk circuit is connected with a busy line, and serves as a signal to the originating operator indi- The rotation of interrupter 27 also causes the intermittent op eration of the low-resistance relay 28 which, when operated, connects an interrupter 30 in circuit with awinding 31 of an induction coil in, the terminating operators telephone set. This produces a series of clicks in the operators receiver, indicating to this terminating operator that the trunk circuit has been connected with the busy line. The intermittent inclusion of the low-resistance relay 28 in parallel with the high-resistance relay 26 causes the intermittent lighting of the trunk supervisory lamp 7 which also serves as a signalto the terminating operator that the plug of the trunk circuit has been connected with a busy line.

What is claimed is: a I

1. A telephone exchange system comprising a trunk circuit extending from a first to a second central office, a cord circuit at the first central office connected withthe trunk circuit, a signaling device in the trunk circuit and located at the second central ofiice, telephone lines terminating at the second central ofiice, a supervisory relay in the trunk circuit energized upon connection thereof with a busy line over a circuit including the contacts of the switchhook, and apparatus controlled by the supervisory relay for causing the intermittent operation oithe signaling device.

2. A telephone exchange system comprising a trunk circuit extending from a first to a second central ofiice, a cord circuit at the first central ofiice connected with the trunk circuit, a signaling device in the trunk circuit and located at the second central oflice, telephone lines terminating at the second central olfice, a supervisory relay in the trunk circuit energized upon connection thereof with a busy line over a circuit including the contacts of the switchhook, a relay controlling the signaling device, and interrupter mechanism controlled by, and brought into circuit relation with the control relay upon the operation of, the supervisory relayto cause the intermittent operation of the signaling device.

3. A telephone exchange system comprising a trunk circuit extending from a first to a second central office, a cord circuit at the first central oflice connected with the trunk circuit, a signaling device in the trunk circuit and located at the second central oflice, a signaling device 1n the cord circuit,

telephone lines terminating at the second central oflice, a supervisory relay in the trunk circuit energized upon connection thereof with a busy line over, a circuit in= cluding the contacts of the switchhook, a relay controlling both signaling devices, and interrupter mechanism controlled by the supervisory relay and cooperating with the control relay to cause the intermittent op eration of both signaling devices.

4. vA telephone exchange system comprising a trunk circuit extending from a first to a second central office, telephone lines terminating at said second central oflice, a sleeve relay associated with the trunk responsive to the connection of the trunk with any line, a ringing relay normally controlled by such sleeve relay for connecting a source of ringing current to the connected line, a supervisory relay responsive upon the connection of the trunk with a closed line, a trip relay responsive upon the closure of an open line, and a relay controlled by the supervisory and trip relays to disable the ring-v ing relay. 7

5. A'telephone exchange system comprising a trunk circuit extending from a first to a second central office, a cord circuit at the first central oflice connected with the trunk circuit, lines terminating in the second central ofiice, a source of ringing current :and a ringing relay associated with the trunk circuit, a supervisory relay included in such trunk circuit responsive to the connection of the trunk with a busy line, and means controlled by said supervisory relay for disabling the ringing relay and for intermittently operating a signal associated with the cord circuit at the second central,

oilice. i

In witness whereof, I hereunto subscribe my name this 22d day of September, ,A. D., 1916. I

HENRY P. OLAUSEN. 

